Transforming Growth Factor Beta-1 in Human Breast Milk and Its Correlation with Infants' Parameters

Role of the biological active components of human milk on long-term growth and neurodevelopmental outcome

Human Milk is the best option for infant feeding; and for this reason, it should be promoted, protected, and supported. HM is an individual-specific-dynamic biofluid, characterized by an extreme variability in its composition. A wealth of literature has investigated how HM is related to healthy development. An association between HM composition, including nutrients and growth-related hormones as well as other bioactive components, and short-term and long-term infant outcomes could support this statement; however, the evidence is limited. In fact, HM composition is difficult to examine as it is dynamic and changes within a single feed, diurnally, according to stage of lactation and between and within populations. The aim of this review is summarizing only the innovative knowledge on the association between HM composition and long-term outcomes: infant growth and neurodevelopment. In this specific contest, macronutrients and historical biological component with well recognized effect were excluded (i.e. LCPUFA, DHA, iodine). Revised articles have been found in MEDLINE using breast milk-related outcomes, neurodevelopment, infant growth, breast milk-related biological factors, biomarkers, biological active components, and constituents as keywords. Moreover, we focus our search on the latest research results.

A review on the safety of growth factors commonly used in cultivated meat production

Growth factors are commonly added to cell culture media in cellular agriculture to mimic the endogenous process of proliferation and differentiation of cells. Many of these growth factors are endogenous to humans and known to be present in the edible tissues and milk of food animals. However, there is little or no information on the use of growth factors intentionally added in food production before the advent of cultivated meat. Ten commonly used growth factors have been reviewed to include information on their mode of action, bioavailability, occurrence in food and food animals, endogenous levels in humans, as well as exposure and toxicological information drawn from relevant animal studies and human clinical trials with a focus on oral exposure. In addition, a comparison of homology of growth factors was done to compare the sequence homology of growth factors from humans and domestic animal species commonly consumed as food, such as bovine, porcine, and poultry. This information has been gathered as the starting point to determine the safety of use of growth factors in cultivated meat meant for human consumption. The change in levels of growth factors measured in human milk and bovine milk after pasteurization and high-temperature treatment is discussed to give an indication of how commercial food processing can affect the levels of growth factors in food. The concept of substantial equivalence is also discussed together with a conservative exposure estimation. More work on how to integrate in silico assessments into the routine safety assessment of growth factors is needed.

Human Milk Bioactive Components and Child Growth and Body Composition in the First 2 Years: A Systematic Review

Human milk (HM) contains macronutrients, micronutrients, and a multitude of other bioactive factors, which can have a long-term impact on infant growth and development. We systematically searched MEDLINE, EMBASE, Cochrane Library, Scopus, and Web of Science to synthesize evidence published between 1980 and 2022 on HM components and anthropometry through 2 y of age among term-born infants. From 9992 abstracts screened, 141 articles were included and categorized based on their reporting of HM micronutrients, macronutrients, or bioactive components. Bioactives including hormones, HM oligosaccharides (HMOs), and immunomodulatory components are reported here, based on 75 articles from 69 unique studies reporting observations from 9980 dyads. Research designs, milk collection strategies, sampling times, geographic and socioeconomic settings, reporting practices, and outcomes varied considerably. Meta-analyses were not possible because data collection times and reporting were inconsistent among the studies included. Few measured infant HM intake, adjusted for confounders, precisely captured breastfeeding exclusivity, or adequately described HM collection protocols. Only 5 studies (6%) had high overall quality scores. Hormones were the most extensively examined bioactive with 46 articles (n = 6773 dyads), compared with 13 (n = 2640 dyads) for HMOs and 12 (n = 1422 dyads) for immunomodulatory components. Two studies conducted untargeted metabolomics. Leptin and adiponectin demonstrated inverse associations with infant growth, although several studies found no associations. No consistent associations were found between individual HMOs and infant growth outcomes. Among immunomodulatory components in HM, IL-6 demonstrated inverse relationships with infant growth. Current research on HM bioactives is largely inconclusive and is insufficient to address the complex composition of HM. Future research should ideally capture HM intake, use biologically relevant anthropometrics, and integrate components across categories, embracing a systems biology approach to better understand how HM components work independently and synergistically to influence infant growth.

Effects of Pre/Probiotic Supplementation on Breast Milk Levels of TGF-b1, TGF-b2, and IgA: A Systematic Review and Meta-Analysis of Randomized-Controlled Trial

Background: Previous studies have proposed that the maternal intake of pre/probiotics may affect the immune composition of breast milk. Nevertheless, the available findings are contradictory. This meta-analysis aimed to examine the impact of maternal supplementation with pre/probiotics on the levels of total immunoglobulin A (IgA), secretory IgA (SIgA), transforming growth factor beta 1 (TGF-β1), and TGF-2 in breast milk. Methods: PubMed and Scopus were systematically searched using a comprehensive search strategy for eligible randomized-controlled trials published up to February 2021. A random-effects model was applied to pool weighted mean difference and 95% confidence interval (CI) as effect size. Cochran's Q statistic and the I2 statistic were used to measure the between-study variance. Egger's regression test was used to assess publication bias. Results: A total of 12 different studies, with a total sample size of 1722 individuals (probiotic group: 858, placebo group: 864), were included in this meta-analysis. In the overall analysis, compared with placebo, maternal supplementation with pre/probiotics had no significant effect on concentrations of total IgA, SIgA, TGF-β1, and TGF-β2 in the breast milk. In the subgroup analysis, pre/probiotics did not affect total IgA, TGF-β1, and TGF-β2 in both colostrum/transitional and mature milk. However, a significant increase in SIgA was found in colostrum/transitional milk following pre/probiotic administration (WMD = 19.33, 95% CI: 0.83-37.83; p = 0.04), without evidence for remarkable heterogeneity (I² = 0.0, p = 0.57). Conclusions: Maternal supplementation with pre/probiotics may increase SIgA in colostrum/transitional milk, without any effect on total IgA, TGF-β1, and TGF-β2.

Hypoallergenic infant formula lacks transforming growth factor beta activity and has a lower anti-inflammatory activity than regular infant formula

Hypoallergenic formulas are recommended for infants who are not breastfed and cannot tolerate cow milk formulas due to allergy. These formulas are hydrolyzed to break down larger protein chains into shorter, easy-to-digest, and potentially less allergenic proteins. Hydrolysis, however, possibly occurs at the expense of the transforming growth factor beta (TGF-β) and anti-inflammatory activity that is inherent in regular formula. Our objective was to determine the TGF-β and the anti-inflammatory activity of commercially available hypoallergenic and regular formulas. Human gingival fibroblasts were incubated with reconstituted formulas followed by detection of TGF-β target genes and activation of Smad2/3 signaling. Gingival fibroblasts and the oral squamous cell carcinoma cell line HSC-2 were also exposed to formulas before adding interleukin (IL)1β and tumor necrosis factor (TNF)α to provoke expression of pro-inflammatory cytokines. For murine bone marrow-derived macrophages, pro-inflammatory cytokine expression was stimulated with saliva. Changes in p65 nuclear translocation and phosphorylation of smad3 and p38 were analyzed by immunostaining. Our study demonstrated that regular formula, but not hypoallergenic formula, enhanced the expression of TGF-β target genes IL11, PRG4, and NOX4 in gingival fibroblasts. Hypoallergenic formulas also failed to initiate nuclear translocation of Smad2/3 and phosphorylation of Smad3. Moreover, regular formulas were more potent than hypoallergenic formulas in reducing the expression of pro-inflammatory cytokines in gingival fibroblasts, HSC-2 epithelial cells, and murine bone marrow macrophages. Hypoallergenic and regular formulas had a similar capacity to reduce p65 nuclear translocation and phosphorylation of p38 in fibroblasts. These findings suggest that hypoallergenic formulas lack in vitro TGF-β activity and have a lower anti-inflammatory activity compared with regular formulas.